The present invention relates generally to a system and method for determining an amount of toner mass present on a toner application surface, and the real-time adjustment of parameters controlling xerographic transfer performance in the system. The present embodiments are also directed to a light-transmissive transfer belt used in the system for determining toner mass amount and methods for making the belt. It is to be appreciated that the following embodiments may be used with both drum or belt photoreceptors and in intermediate transfer belt (ITB) and biased transfer belt (BTB) and biased transfer roll (BTR) systems.
Conventional printing devices exist in which a photoreceptor belt is used to provide toner mass to a base medium (e.g., paper). In order to accurately control the amount of toner mass being delivered to the base medium, these devices may include transfer systems that determine the amount of toner mass being transferred to and carried by the photoreceptor belt. With each generation of printing devices, it is desirable to enhance xerographic performance through use and control of the transfer systems.
Optical sensors are known and used in printing systems to detect transferred toner mass amounts through reflectance measurements. For example, U.S. Publication No. 2008/0089708, discloses use of optical reflective-based sensors to generate and compute reflection outputs to determine an amount of toner mass present on the toner application surface. However, these sensors have significant limitations. In particular, current optical reflective based sensors are unable to measure masses beyond a certain amount and are not capable of providing fine or ultra fine details about pre- or post-transferred images. Moreover, the systems using such sensors tend to be temperamental and sensitive to changes to the photoreceptor belt, and/or other components of the printing device, that occur due to wear. For example, the surface of the photoreceptor belt may degrade over time such that surfaces on the belt become less reflective, less uniform, etc. This may cause light that is directed to the belt (e.g., for the purpose of measuring the amount of toner mass present, etc.) to be “lost” in the system through absorption, scattering, and/or transmission. The loss of light caused by imperfections in the belt, and/or other components of the printing device may require relatively frequent calibration of the device using a relatively intricate and time consuming process. It is well known that transfer set points are a strong function of such key time varying “noise” factors such as belt material properties, paper states, and environmental variation. Unfortunately, each of these can interact in a complex and difficult to control manner.
Thus, new and effective means to provide accurate sensing of toner mass on transfer belts is important to future enhancement of toner transfer and overall xerographic performance. In this regard, a transfer system that can provide real-time measurement and feedback of critical xerographic control parameters or variables will be highly desirable. There are currently no transfer systems that can provide precise transfer control and real-time feedback for optimization of the xerographic transfer process.